// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2014 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_SPARSE_CWISE_BINARY_OP_H
#define EIGEN_SPARSE_CWISE_BINARY_OP_H

namespace Eigen {

// Here we have to handle 3 cases:
//  1 - sparse op dense
//  2 - dense op sparse
//  3 - sparse op sparse
// We also need to implement a 4th iterator for:
//  4 - dense op dense
// Finally, we also need to distinguish between the product and other operations :
//                configuration      returned mode
//  1 - sparse op dense    product      sparse
//                         generic      dense
//  2 - dense op sparse    product      sparse
//                         generic      dense
//  3 - sparse op sparse   product      sparse
//                         generic      sparse
//  4 - dense op dense     product      dense
//                         generic      dense
//
// TODO to ease compiler job, we could specialize product/quotient with a scalar
//      and fallback to cwise-unary evaluator using bind1st_op and bind2nd_op.

template <typename BinaryOp, typename Lhs, typename Rhs>
class CwiseBinaryOpImpl<BinaryOp, Lhs, Rhs, Sparse> : public SparseMatrixBase<CwiseBinaryOp<BinaryOp, Lhs, Rhs>>
{
public:
    typedef CwiseBinaryOp<BinaryOp, Lhs, Rhs> Derived;
    typedef SparseMatrixBase<Derived> Base;
    EIGEN_SPARSE_PUBLIC_INTERFACE(Derived)
    CwiseBinaryOpImpl()
    {
        EIGEN_STATIC_ASSERT(((!internal::is_same<typename internal::traits<Lhs>::StorageKind, typename internal::traits<Rhs>::StorageKind>::value) ||
                             ((internal::evaluator<Lhs>::Flags & RowMajorBit) == (internal::evaluator<Rhs>::Flags & RowMajorBit))),
                            THE_STORAGE_ORDER_OF_BOTH_SIDES_MUST_MATCH);
    }
};

namespace internal {

    // Generic "sparse OP sparse"
    template <typename XprType> struct binary_sparse_evaluator;

    template <typename BinaryOp, typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<BinaryOp, Lhs, Rhs>, IteratorBased, IteratorBased> : evaluator_base<CwiseBinaryOp<BinaryOp, Lhs, Rhs>>
    {
    protected:
        typedef typename evaluator<Lhs>::InnerIterator LhsIterator;
        typedef typename evaluator<Rhs>::InnerIterator RhsIterator;
        typedef CwiseBinaryOp<BinaryOp, Lhs, Rhs> XprType;
        typedef typename traits<XprType>::Scalar Scalar;
        typedef typename XprType::StorageIndex StorageIndex;

    public:
        class InnerIterator
        {
        public:
            EIGEN_STRONG_INLINE InnerIterator(const binary_evaluator& aEval, Index outer)
                : m_lhsIter(aEval.m_lhsImpl, outer), m_rhsIter(aEval.m_rhsImpl, outer), m_functor(aEval.m_functor)
            {
                this->operator++();
            }

            EIGEN_STRONG_INLINE InnerIterator& operator++()
            {
                if (m_lhsIter && m_rhsIter && (m_lhsIter.index() == m_rhsIter.index()))
                {
                    m_id = m_lhsIter.index();
                    m_value = m_functor(m_lhsIter.value(), m_rhsIter.value());
                    ++m_lhsIter;
                    ++m_rhsIter;
                }
                else if (m_lhsIter && (!m_rhsIter || (m_lhsIter.index() < m_rhsIter.index())))
                {
                    m_id = m_lhsIter.index();
                    m_value = m_functor(m_lhsIter.value(), Scalar(0));
                    ++m_lhsIter;
                }
                else if (m_rhsIter && (!m_lhsIter || (m_lhsIter.index() > m_rhsIter.index())))
                {
                    m_id = m_rhsIter.index();
                    m_value = m_functor(Scalar(0), m_rhsIter.value());
                    ++m_rhsIter;
                }
                else
                {
                    m_value = Scalar(0);  // this is to avoid a compilation warning
                    m_id = -1;
                }
                return *this;
            }

            EIGEN_STRONG_INLINE Scalar value() const { return m_value; }

            EIGEN_STRONG_INLINE StorageIndex index() const { return m_id; }
            EIGEN_STRONG_INLINE Index outer() const { return m_lhsIter.outer(); }
            EIGEN_STRONG_INLINE Index row() const { return Lhs::IsRowMajor ? m_lhsIter.row() : index(); }
            EIGEN_STRONG_INLINE Index col() const { return Lhs::IsRowMajor ? index() : m_lhsIter.col(); }

            EIGEN_STRONG_INLINE operator bool() const { return m_id >= 0; }

        protected:
            LhsIterator m_lhsIter;
            RhsIterator m_rhsIter;
            const BinaryOp& m_functor;
            Scalar m_value;
            StorageIndex m_id;
        };

        enum
        {
            CoeffReadCost = int(evaluator<Lhs>::CoeffReadCost) + int(evaluator<Rhs>::CoeffReadCost) + int(functor_traits<BinaryOp>::Cost),
            Flags = XprType::Flags
        };

        explicit binary_evaluator(const XprType& xpr) : m_functor(xpr.functor()), m_lhsImpl(xpr.lhs()), m_rhsImpl(xpr.rhs())
        {
            EIGEN_INTERNAL_CHECK_COST_VALUE(functor_traits<BinaryOp>::Cost);
            EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
        }

        inline Index nonZerosEstimate() const { return m_lhsImpl.nonZerosEstimate() + m_rhsImpl.nonZerosEstimate(); }

    protected:
        const BinaryOp m_functor;
        evaluator<Lhs> m_lhsImpl;
        evaluator<Rhs> m_rhsImpl;
    };

    // dense op sparse
    template <typename BinaryOp, typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<BinaryOp, Lhs, Rhs>, IndexBased, IteratorBased> : evaluator_base<CwiseBinaryOp<BinaryOp, Lhs, Rhs>>
    {
    protected:
        typedef typename evaluator<Rhs>::InnerIterator RhsIterator;
        typedef CwiseBinaryOp<BinaryOp, Lhs, Rhs> XprType;
        typedef typename traits<XprType>::Scalar Scalar;
        typedef typename XprType::StorageIndex StorageIndex;

    public:
        class InnerIterator
        {
            enum
            {
                IsRowMajor = (int(Rhs::Flags) & RowMajorBit) == RowMajorBit
            };

        public:
            EIGEN_STRONG_INLINE InnerIterator(const binary_evaluator& aEval, Index outer)
                : m_lhsEval(aEval.m_lhsImpl), m_rhsIter(aEval.m_rhsImpl, outer), m_functor(aEval.m_functor), m_value(0), m_id(-1),
                  m_innerSize(aEval.m_expr.rhs().innerSize())
            {
                this->operator++();
            }

            EIGEN_STRONG_INLINE InnerIterator& operator++()
            {
                ++m_id;
                if (m_id < m_innerSize)
                {
                    Scalar lhsVal = m_lhsEval.coeff(IsRowMajor ? m_rhsIter.outer() : m_id, IsRowMajor ? m_id : m_rhsIter.outer());
                    if (m_rhsIter && m_rhsIter.index() == m_id)
                    {
                        m_value = m_functor(lhsVal, m_rhsIter.value());
                        ++m_rhsIter;
                    }
                    else
                        m_value = m_functor(lhsVal, Scalar(0));
                }

                return *this;
            }

            EIGEN_STRONG_INLINE Scalar value() const
            {
                eigen_internal_assert(m_id < m_innerSize);
                return m_value;
            }

            EIGEN_STRONG_INLINE StorageIndex index() const { return m_id; }
            EIGEN_STRONG_INLINE Index outer() const { return m_rhsIter.outer(); }
            EIGEN_STRONG_INLINE Index row() const { return IsRowMajor ? m_rhsIter.outer() : m_id; }
            EIGEN_STRONG_INLINE Index col() const { return IsRowMajor ? m_id : m_rhsIter.outer(); }

            EIGEN_STRONG_INLINE operator bool() const { return m_id < m_innerSize; }

        protected:
            const evaluator<Lhs>& m_lhsEval;
            RhsIterator m_rhsIter;
            const BinaryOp& m_functor;
            Scalar m_value;
            StorageIndex m_id;
            StorageIndex m_innerSize;
        };

        enum
        {
            CoeffReadCost = int(evaluator<Lhs>::CoeffReadCost) + int(evaluator<Rhs>::CoeffReadCost) + int(functor_traits<BinaryOp>::Cost),
            Flags = XprType::Flags
        };

        explicit binary_evaluator(const XprType& xpr) : m_functor(xpr.functor()), m_lhsImpl(xpr.lhs()), m_rhsImpl(xpr.rhs()), m_expr(xpr)
        {
            EIGEN_INTERNAL_CHECK_COST_VALUE(functor_traits<BinaryOp>::Cost);
            EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
        }

        inline Index nonZerosEstimate() const { return m_expr.size(); }

    protected:
        const BinaryOp m_functor;
        evaluator<Lhs> m_lhsImpl;
        evaluator<Rhs> m_rhsImpl;
        const XprType& m_expr;
    };

    // sparse op dense
    template <typename BinaryOp, typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<BinaryOp, Lhs, Rhs>, IteratorBased, IndexBased> : evaluator_base<CwiseBinaryOp<BinaryOp, Lhs, Rhs>>
    {
    protected:
        typedef typename evaluator<Lhs>::InnerIterator LhsIterator;
        typedef CwiseBinaryOp<BinaryOp, Lhs, Rhs> XprType;
        typedef typename traits<XprType>::Scalar Scalar;
        typedef typename XprType::StorageIndex StorageIndex;

    public:
        class InnerIterator
        {
            enum
            {
                IsRowMajor = (int(Lhs::Flags) & RowMajorBit) == RowMajorBit
            };

        public:
            EIGEN_STRONG_INLINE InnerIterator(const binary_evaluator& aEval, Index outer)
                : m_lhsIter(aEval.m_lhsImpl, outer), m_rhsEval(aEval.m_rhsImpl), m_functor(aEval.m_functor), m_value(0), m_id(-1),
                  m_innerSize(aEval.m_expr.lhs().innerSize())
            {
                this->operator++();
            }

            EIGEN_STRONG_INLINE InnerIterator& operator++()
            {
                ++m_id;
                if (m_id < m_innerSize)
                {
                    Scalar rhsVal = m_rhsEval.coeff(IsRowMajor ? m_lhsIter.outer() : m_id, IsRowMajor ? m_id : m_lhsIter.outer());
                    if (m_lhsIter && m_lhsIter.index() == m_id)
                    {
                        m_value = m_functor(m_lhsIter.value(), rhsVal);
                        ++m_lhsIter;
                    }
                    else
                        m_value = m_functor(Scalar(0), rhsVal);
                }

                return *this;
            }

            EIGEN_STRONG_INLINE Scalar value() const
            {
                eigen_internal_assert(m_id < m_innerSize);
                return m_value;
            }

            EIGEN_STRONG_INLINE StorageIndex index() const { return m_id; }
            EIGEN_STRONG_INLINE Index outer() const { return m_lhsIter.outer(); }
            EIGEN_STRONG_INLINE Index row() const { return IsRowMajor ? m_lhsIter.outer() : m_id; }
            EIGEN_STRONG_INLINE Index col() const { return IsRowMajor ? m_id : m_lhsIter.outer(); }

            EIGEN_STRONG_INLINE operator bool() const { return m_id < m_innerSize; }

        protected:
            LhsIterator m_lhsIter;
            const evaluator<Rhs>& m_rhsEval;
            const BinaryOp& m_functor;
            Scalar m_value;
            StorageIndex m_id;
            StorageIndex m_innerSize;
        };

        enum
        {
            CoeffReadCost = int(evaluator<Lhs>::CoeffReadCost) + int(evaluator<Rhs>::CoeffReadCost) + int(functor_traits<BinaryOp>::Cost),
            Flags = XprType::Flags
        };

        explicit binary_evaluator(const XprType& xpr) : m_functor(xpr.functor()), m_lhsImpl(xpr.lhs()), m_rhsImpl(xpr.rhs()), m_expr(xpr)
        {
            EIGEN_INTERNAL_CHECK_COST_VALUE(functor_traits<BinaryOp>::Cost);
            EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
        }

        inline Index nonZerosEstimate() const { return m_expr.size(); }

    protected:
        const BinaryOp m_functor;
        evaluator<Lhs> m_lhsImpl;
        evaluator<Rhs> m_rhsImpl;
        const XprType& m_expr;
    };

    template <typename T,
              typename LhsKind = typename evaluator_traits<typename T::Lhs>::Kind,
              typename RhsKind = typename evaluator_traits<typename T::Rhs>::Kind,
              typename LhsScalar = typename traits<typename T::Lhs>::Scalar,
              typename RhsScalar = typename traits<typename T::Rhs>::Scalar>
    struct sparse_conjunction_evaluator;

    // "sparse .* sparse"
    template <typename T1, typename T2, typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<scalar_product_op<T1, T2>, Lhs, Rhs>, IteratorBased, IteratorBased>
        : sparse_conjunction_evaluator<CwiseBinaryOp<scalar_product_op<T1, T2>, Lhs, Rhs>>
    {
        typedef CwiseBinaryOp<scalar_product_op<T1, T2>, Lhs, Rhs> XprType;
        typedef sparse_conjunction_evaluator<XprType> Base;
        explicit binary_evaluator(const XprType& xpr) : Base(xpr) {}
    };
    // "dense .* sparse"
    template <typename T1, typename T2, typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<scalar_product_op<T1, T2>, Lhs, Rhs>, IndexBased, IteratorBased>
        : sparse_conjunction_evaluator<CwiseBinaryOp<scalar_product_op<T1, T2>, Lhs, Rhs>>
    {
        typedef CwiseBinaryOp<scalar_product_op<T1, T2>, Lhs, Rhs> XprType;
        typedef sparse_conjunction_evaluator<XprType> Base;
        explicit binary_evaluator(const XprType& xpr) : Base(xpr) {}
    };
    // "sparse .* dense"
    template <typename T1, typename T2, typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<scalar_product_op<T1, T2>, Lhs, Rhs>, IteratorBased, IndexBased>
        : sparse_conjunction_evaluator<CwiseBinaryOp<scalar_product_op<T1, T2>, Lhs, Rhs>>
    {
        typedef CwiseBinaryOp<scalar_product_op<T1, T2>, Lhs, Rhs> XprType;
        typedef sparse_conjunction_evaluator<XprType> Base;
        explicit binary_evaluator(const XprType& xpr) : Base(xpr) {}
    };

    // "sparse ./ dense"
    template <typename T1, typename T2, typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<scalar_quotient_op<T1, T2>, Lhs, Rhs>, IteratorBased, IndexBased>
        : sparse_conjunction_evaluator<CwiseBinaryOp<scalar_quotient_op<T1, T2>, Lhs, Rhs>>
    {
        typedef CwiseBinaryOp<scalar_quotient_op<T1, T2>, Lhs, Rhs> XprType;
        typedef sparse_conjunction_evaluator<XprType> Base;
        explicit binary_evaluator(const XprType& xpr) : Base(xpr) {}
    };

    // "sparse && sparse"
    template <typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<scalar_boolean_and_op, Lhs, Rhs>, IteratorBased, IteratorBased>
        : sparse_conjunction_evaluator<CwiseBinaryOp<scalar_boolean_and_op, Lhs, Rhs>>
    {
        typedef CwiseBinaryOp<scalar_boolean_and_op, Lhs, Rhs> XprType;
        typedef sparse_conjunction_evaluator<XprType> Base;
        explicit binary_evaluator(const XprType& xpr) : Base(xpr) {}
    };
    // "dense && sparse"
    template <typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<scalar_boolean_and_op, Lhs, Rhs>, IndexBased, IteratorBased>
        : sparse_conjunction_evaluator<CwiseBinaryOp<scalar_boolean_and_op, Lhs, Rhs>>
    {
        typedef CwiseBinaryOp<scalar_boolean_and_op, Lhs, Rhs> XprType;
        typedef sparse_conjunction_evaluator<XprType> Base;
        explicit binary_evaluator(const XprType& xpr) : Base(xpr) {}
    };
    // "sparse && dense"
    template <typename Lhs, typename Rhs>
    struct binary_evaluator<CwiseBinaryOp<scalar_boolean_and_op, Lhs, Rhs>, IteratorBased, IndexBased>
        : sparse_conjunction_evaluator<CwiseBinaryOp<scalar_boolean_and_op, Lhs, Rhs>>
    {
        typedef CwiseBinaryOp<scalar_boolean_and_op, Lhs, Rhs> XprType;
        typedef sparse_conjunction_evaluator<XprType> Base;
        explicit binary_evaluator(const XprType& xpr) : Base(xpr) {}
    };

    // "sparse ^ sparse"
    template <typename XprType> struct sparse_conjunction_evaluator<XprType, IteratorBased, IteratorBased> : evaluator_base<XprType>
    {
    protected:
        typedef typename XprType::Functor BinaryOp;
        typedef typename XprType::Lhs LhsArg;
        typedef typename XprType::Rhs RhsArg;
        typedef typename evaluator<LhsArg>::InnerIterator LhsIterator;
        typedef typename evaluator<RhsArg>::InnerIterator RhsIterator;
        typedef typename XprType::StorageIndex StorageIndex;
        typedef typename traits<XprType>::Scalar Scalar;

    public:
        class InnerIterator
        {
        public:
            EIGEN_STRONG_INLINE InnerIterator(const sparse_conjunction_evaluator& aEval, Index outer)
                : m_lhsIter(aEval.m_lhsImpl, outer), m_rhsIter(aEval.m_rhsImpl, outer), m_functor(aEval.m_functor)
            {
                while (m_lhsIter && m_rhsIter && (m_lhsIter.index() != m_rhsIter.index()))
                {
                    if (m_lhsIter.index() < m_rhsIter.index())
                        ++m_lhsIter;
                    else
                        ++m_rhsIter;
                }
            }

            EIGEN_STRONG_INLINE InnerIterator& operator++()
            {
                ++m_lhsIter;
                ++m_rhsIter;
                while (m_lhsIter && m_rhsIter && (m_lhsIter.index() != m_rhsIter.index()))
                {
                    if (m_lhsIter.index() < m_rhsIter.index())
                        ++m_lhsIter;
                    else
                        ++m_rhsIter;
                }
                return *this;
            }

            EIGEN_STRONG_INLINE Scalar value() const { return m_functor(m_lhsIter.value(), m_rhsIter.value()); }

            EIGEN_STRONG_INLINE StorageIndex index() const { return m_lhsIter.index(); }
            EIGEN_STRONG_INLINE Index outer() const { return m_lhsIter.outer(); }
            EIGEN_STRONG_INLINE Index row() const { return m_lhsIter.row(); }
            EIGEN_STRONG_INLINE Index col() const { return m_lhsIter.col(); }

            EIGEN_STRONG_INLINE operator bool() const { return (m_lhsIter && m_rhsIter); }

        protected:
            LhsIterator m_lhsIter;
            RhsIterator m_rhsIter;
            const BinaryOp& m_functor;
        };

        enum
        {
            CoeffReadCost = int(evaluator<LhsArg>::CoeffReadCost) + int(evaluator<RhsArg>::CoeffReadCost) + int(functor_traits<BinaryOp>::Cost),
            Flags = XprType::Flags
        };

        explicit sparse_conjunction_evaluator(const XprType& xpr) : m_functor(xpr.functor()), m_lhsImpl(xpr.lhs()), m_rhsImpl(xpr.rhs())
        {
            EIGEN_INTERNAL_CHECK_COST_VALUE(functor_traits<BinaryOp>::Cost);
            EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
        }

        inline Index nonZerosEstimate() const { return (std::min)(m_lhsImpl.nonZerosEstimate(), m_rhsImpl.nonZerosEstimate()); }

    protected:
        const BinaryOp m_functor;
        evaluator<LhsArg> m_lhsImpl;
        evaluator<RhsArg> m_rhsImpl;
    };

    // "dense ^ sparse"
    template <typename XprType> struct sparse_conjunction_evaluator<XprType, IndexBased, IteratorBased> : evaluator_base<XprType>
    {
    protected:
        typedef typename XprType::Functor BinaryOp;
        typedef typename XprType::Lhs LhsArg;
        typedef typename XprType::Rhs RhsArg;
        typedef evaluator<LhsArg> LhsEvaluator;
        typedef typename evaluator<RhsArg>::InnerIterator RhsIterator;
        typedef typename XprType::StorageIndex StorageIndex;
        typedef typename traits<XprType>::Scalar Scalar;

    public:
        class InnerIterator
        {
            enum
            {
                IsRowMajor = (int(RhsArg::Flags) & RowMajorBit) == RowMajorBit
            };

        public:
            EIGEN_STRONG_INLINE InnerIterator(const sparse_conjunction_evaluator& aEval, Index outer)
                : m_lhsEval(aEval.m_lhsImpl), m_rhsIter(aEval.m_rhsImpl, outer), m_functor(aEval.m_functor), m_outer(outer)
            {
            }

            EIGEN_STRONG_INLINE InnerIterator& operator++()
            {
                ++m_rhsIter;
                return *this;
            }

            EIGEN_STRONG_INLINE Scalar value() const
            {
                return m_functor(m_lhsEval.coeff(IsRowMajor ? m_outer : m_rhsIter.index(), IsRowMajor ? m_rhsIter.index() : m_outer), m_rhsIter.value());
            }

            EIGEN_STRONG_INLINE StorageIndex index() const { return m_rhsIter.index(); }
            EIGEN_STRONG_INLINE Index outer() const { return m_rhsIter.outer(); }
            EIGEN_STRONG_INLINE Index row() const { return m_rhsIter.row(); }
            EIGEN_STRONG_INLINE Index col() const { return m_rhsIter.col(); }

            EIGEN_STRONG_INLINE operator bool() const { return m_rhsIter; }

        protected:
            const LhsEvaluator& m_lhsEval;
            RhsIterator m_rhsIter;
            const BinaryOp& m_functor;
            const Index m_outer;
        };

        enum
        {
            CoeffReadCost = int(evaluator<LhsArg>::CoeffReadCost) + int(evaluator<RhsArg>::CoeffReadCost) + int(functor_traits<BinaryOp>::Cost),
            Flags = XprType::Flags
        };

        explicit sparse_conjunction_evaluator(const XprType& xpr) : m_functor(xpr.functor()), m_lhsImpl(xpr.lhs()), m_rhsImpl(xpr.rhs())
        {
            EIGEN_INTERNAL_CHECK_COST_VALUE(functor_traits<BinaryOp>::Cost);
            EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
        }

        inline Index nonZerosEstimate() const { return m_rhsImpl.nonZerosEstimate(); }

    protected:
        const BinaryOp m_functor;
        evaluator<LhsArg> m_lhsImpl;
        evaluator<RhsArg> m_rhsImpl;
    };

    // "sparse ^ dense"
    template <typename XprType> struct sparse_conjunction_evaluator<XprType, IteratorBased, IndexBased> : evaluator_base<XprType>
    {
    protected:
        typedef typename XprType::Functor BinaryOp;
        typedef typename XprType::Lhs LhsArg;
        typedef typename XprType::Rhs RhsArg;
        typedef typename evaluator<LhsArg>::InnerIterator LhsIterator;
        typedef evaluator<RhsArg> RhsEvaluator;
        typedef typename XprType::StorageIndex StorageIndex;
        typedef typename traits<XprType>::Scalar Scalar;

    public:
        class InnerIterator
        {
            enum
            {
                IsRowMajor = (int(LhsArg::Flags) & RowMajorBit) == RowMajorBit
            };

        public:
            EIGEN_STRONG_INLINE InnerIterator(const sparse_conjunction_evaluator& aEval, Index outer)
                : m_lhsIter(aEval.m_lhsImpl, outer), m_rhsEval(aEval.m_rhsImpl), m_functor(aEval.m_functor), m_outer(outer)
            {
            }

            EIGEN_STRONG_INLINE InnerIterator& operator++()
            {
                ++m_lhsIter;
                return *this;
            }

            EIGEN_STRONG_INLINE Scalar value() const
            {
                return m_functor(m_lhsIter.value(), m_rhsEval.coeff(IsRowMajor ? m_outer : m_lhsIter.index(), IsRowMajor ? m_lhsIter.index() : m_outer));
            }

            EIGEN_STRONG_INLINE StorageIndex index() const { return m_lhsIter.index(); }
            EIGEN_STRONG_INLINE Index outer() const { return m_lhsIter.outer(); }
            EIGEN_STRONG_INLINE Index row() const { return m_lhsIter.row(); }
            EIGEN_STRONG_INLINE Index col() const { return m_lhsIter.col(); }

            EIGEN_STRONG_INLINE operator bool() const { return m_lhsIter; }

        protected:
            LhsIterator m_lhsIter;
            const evaluator<RhsArg>& m_rhsEval;
            const BinaryOp& m_functor;
            const Index m_outer;
        };

        enum
        {
            CoeffReadCost = int(evaluator<LhsArg>::CoeffReadCost) + int(evaluator<RhsArg>::CoeffReadCost) + int(functor_traits<BinaryOp>::Cost),
            Flags = XprType::Flags
        };

        explicit sparse_conjunction_evaluator(const XprType& xpr) : m_functor(xpr.functor()), m_lhsImpl(xpr.lhs()), m_rhsImpl(xpr.rhs())
        {
            EIGEN_INTERNAL_CHECK_COST_VALUE(functor_traits<BinaryOp>::Cost);
            EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
        }

        inline Index nonZerosEstimate() const { return m_lhsImpl.nonZerosEstimate(); }

    protected:
        const BinaryOp m_functor;
        evaluator<LhsArg> m_lhsImpl;
        evaluator<RhsArg> m_rhsImpl;
    };

}  // namespace internal

/***************************************************************************
* Implementation of SparseMatrixBase and SparseCwise functions/operators
***************************************************************************/

template <typename Derived> template <typename OtherDerived> Derived& SparseMatrixBase<Derived>::operator+=(const EigenBase<OtherDerived>& other)
{
    call_assignment(derived(), other.derived(), internal::add_assign_op<Scalar, typename OtherDerived::Scalar>());
    return derived();
}

template <typename Derived> template <typename OtherDerived> Derived& SparseMatrixBase<Derived>::operator-=(const EigenBase<OtherDerived>& other)
{
    call_assignment(derived(), other.derived(), internal::assign_op<Scalar, typename OtherDerived::Scalar>());
    return derived();
}

template <typename Derived>
template <typename OtherDerived>
EIGEN_STRONG_INLINE Derived& SparseMatrixBase<Derived>::operator-=(const SparseMatrixBase<OtherDerived>& other)
{
    return derived() = derived() - other.derived();
}

template <typename Derived>
template <typename OtherDerived>
EIGEN_STRONG_INLINE Derived& SparseMatrixBase<Derived>::operator+=(const SparseMatrixBase<OtherDerived>& other)
{
    return derived() = derived() + other.derived();
}

template <typename Derived> template <typename OtherDerived> Derived& SparseMatrixBase<Derived>::operator+=(const DiagonalBase<OtherDerived>& other)
{
    call_assignment_no_alias(derived(), other.derived(), internal::add_assign_op<Scalar, typename OtherDerived::Scalar>());
    return derived();
}

template <typename Derived> template <typename OtherDerived> Derived& SparseMatrixBase<Derived>::operator-=(const DiagonalBase<OtherDerived>& other)
{
    call_assignment_no_alias(derived(), other.derived(), internal::sub_assign_op<Scalar, typename OtherDerived::Scalar>());
    return derived();
}

template <typename Derived>
template <typename OtherDerived>
EIGEN_STRONG_INLINE const typename SparseMatrixBase<Derived>::template CwiseProductDenseReturnType<OtherDerived>::Type
SparseMatrixBase<Derived>::cwiseProduct(const MatrixBase<OtherDerived>& other) const
{
    return typename CwiseProductDenseReturnType<OtherDerived>::Type(derived(), other.derived());
}

template <typename DenseDerived, typename SparseDerived>
EIGEN_STRONG_INLINE const
    CwiseBinaryOp<internal::scalar_sum_op<typename DenseDerived::Scalar, typename SparseDerived::Scalar>, const DenseDerived, const SparseDerived>
    operator+(const MatrixBase<DenseDerived>& a, const SparseMatrixBase<SparseDerived>& b)
{
    return CwiseBinaryOp<internal::scalar_sum_op<typename DenseDerived::Scalar, typename SparseDerived::Scalar>, const DenseDerived, const SparseDerived>(
        a.derived(), b.derived());
}

template <typename SparseDerived, typename DenseDerived>
EIGEN_STRONG_INLINE const
    CwiseBinaryOp<internal::scalar_sum_op<typename SparseDerived::Scalar, typename DenseDerived::Scalar>, const SparseDerived, const DenseDerived>
    operator+(const SparseMatrixBase<SparseDerived>& a, const MatrixBase<DenseDerived>& b)
{
    return CwiseBinaryOp<internal::scalar_sum_op<typename SparseDerived::Scalar, typename DenseDerived::Scalar>, const SparseDerived, const DenseDerived>(
        a.derived(), b.derived());
}

template <typename DenseDerived, typename SparseDerived>
EIGEN_STRONG_INLINE const
    CwiseBinaryOp<internal::scalar_difference_op<typename DenseDerived::Scalar, typename SparseDerived::Scalar>, const DenseDerived, const SparseDerived>
    operator-(const MatrixBase<DenseDerived>& a, const SparseMatrixBase<SparseDerived>& b)
{
    return CwiseBinaryOp<internal::scalar_difference_op<typename DenseDerived::Scalar, typename SparseDerived::Scalar>,
                         const DenseDerived,
                         const SparseDerived>(a.derived(), b.derived());
}

template <typename SparseDerived, typename DenseDerived>
EIGEN_STRONG_INLINE const
    CwiseBinaryOp<internal::scalar_difference_op<typename SparseDerived::Scalar, typename DenseDerived::Scalar>, const SparseDerived, const DenseDerived>
    operator-(const SparseMatrixBase<SparseDerived>& a, const MatrixBase<DenseDerived>& b)
{
    return CwiseBinaryOp<internal::scalar_difference_op<typename SparseDerived::Scalar, typename DenseDerived::Scalar>,
                         const SparseDerived,
                         const DenseDerived>(a.derived(), b.derived());
}

}  // end namespace Eigen

#endif  // EIGEN_SPARSE_CWISE_BINARY_OP_H
